%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Esawy, Mona A.
%A Combet-Blanc, Yannick
%T Immobilization of Bacillus licheniformis 5A1 milk-clotting enzyme and characterization of its enzyme properties
%D 2006
%L PAR00001778
%G ENG
%J World Journal of Microbiology and Biotechnology
%@ 0959-3993
%K Bacillus licheniformis ; immobilization ; milk clotting enzyme
%M CC:0002363723-0001
%N 3
%P 197-200
%R 10.1007/s11274-005-9018-z
%U https://www.documentation.ird.fr/hor/PAR00001778
%> https://www.documentation.ird.fr/intranet/publi/2007/suppl/010037785.pdf
%V 22
%W Horizon (IRD)
%X Milk-clotting enzyme from Bacillus licheniformis 5A1 was immobilized on Amberlite IR-120 by ionic binding. Almost all the enzyme activity was retained on the support. The immobilized milk-clotting enzyme was repeatedly used to produce cheese in a batch reactor. The production of cheese was repeated 5 times with no loss of activity. The specific activity calculated on a bound-protein basis was slightly higher than that of free enzyme. The free and immobilized enzyme were highly tolerant to repeated freezing and thawing. The optimum temperature for milk-clotting activity was 70 degrees C with the free enzyme whereas, it was ranged from 70 to 80 degrees C with the immobilized milk-clotting enzyme. The activation energy (E-A) of the immobilized milk-clotting enzyme was lower than the free enzyme (E-A = 1.59 and 1.99 Kcal mol(-1) respectively). The immobilized milk-clotting enzyme exhibited great thermal stability. The milk-clotting optimum pH was 7.0 for both free and immobilized enzyme. The Michaelis constant K-m of the immobilized milk-clotting enzyme was slightly lower than the free enzyme.
%$ 084